Due to aesthetic and safety considerations, utilities such as electricity, telephone, water and gas lines are often supplied from underground lines. The most common means of installing such lines is the cut and cover technique, where a ditch is first dug in the area where the line is desired. The utility line is then installed in the ditch and the ditch covered. This technique is most satisfactory for new construction.
In built up areas the cut and cover technique has a number of problems. First, a ditch often cannot be dug without disturbing existing structures and traffic areas. Digging the trench also creates a greatly increased chance of disturbing existing utility lines. Finally, the trench after refilling, often remains as a partial obstruction to traffic.
For the above reasons, a number of means of boring through unconsolidated material such as soil have been proposed. To date none of the boring methods have met with widespread commerical adoption for a number of reasons.